Self-locking box



Patented Sept. 16, 1952 UNITED STATES PATENT OFFICE SELF-LOCKING Box Thomas Ochar, Little Falls, N. Y.

Application November 9, 1950, Serial No. 194,740

2 Claims. 1

This invention relates to containers, and more particularly to boxes formed of sheet material.

It has heretofore been proposed to provide such boxes with marginal stop lugs, so arranged that when the cover is applied,the stop lugs snappast each other and interlock, to hold the'cover on without the necessity of tying it.

An object of the presentinvention is to devise an improved method of constructing such a box from a folded blank of sheet material, whereby the boxes, having the lugs formed integral therewith, may be easily and cheaply manufactured.

Another object is to devise a box of this general character designed especially to contain compressible material, and so constructed that it may be filled above its top with such material, and the cover then applied to force down and compress the material and to hold it under compression. p

In order that the invention may be readily understood, reference is had to the accompanying drawings forming part of this specification, and in which- Fig. 1 is a fragmentary perspective of one corner of the top or cover portion'of my improved box;

Fig. 2 is a fragmentary view showing the method of cutting and folding a blank to form the box corner shown in Fig. 1; j

Fig. 3 is a perspective view similar to Fig. 1, but showing a corner of the bottom or body portion of the box;

Figs. 4 and 5 are fragmentary transverse sections on an enlarged scale taken substantially on tthe line 55 of Fig. 6 looking in the direction of the arrows, these two figures showing the parts in diiferent positions; and

Fig. 6 is a perspective view on a smaller scale showing the complete box as it appears when filled and locked, as illustrated in Fig. 5.

Referring to the drawings in detail, my improved box comprises a top or cover portionA and a bottom or body portion B. While these two portions are shown as of substantially the same depth or height, it will be understood that the body portion may be of any desired depth or height.

The top or cover portion A consists of a top panel a, end panels b and side panels c. As shown in Fig. 2, the end and side panels b and c are separated from the top panel a by fold lines dand e, as usual.

Two of the opposite panels, as forexample the end panels I), are formed at their ends with a pair of integral flaps f and h, the flap f being preferably wider than the flap h and being connected with the panel I) by fold line 9, and the flap h being connected with the panel b by a fold line i. The flap h itself is formed with a pair of equally spaced additional fold lines a and k.

In forming the cover portion from the blank shown in Fig. 2, the side'and end panels are folded to a position at to the top panel and to each other, in the usual manner. The flap h, which is adjacent the edge of the panel b and is relatively narrow, is then folded down along the line i into a position parallel with the adjacent side panel c. It is then folded back upon itself along the line a' and then again folded at the line It so that it lies against the panel b, the fold 7 lines 2' and k registering with each other.

The folding of the flap h in the manner described forms a stop lug of double thickness as clearly shown in Fig. 1, and this lug is firmly secured to theadiacent panel 0 by means of staples or similar fastening means m.

. The other flap 1, extending from the panel b, is then folded down along the line 9 against the panel 0, and secured to such panel by means of staples m as shown in Fig. 1. vIt will be noted that It will further be noted that the folded lug- I forming flap h is secured fiat against the inside of the panel 0, while the additional flap 1 is secured against the outside of this panel. This leaves the inside of the box cover free from projeotions except for the lugs formed by the'flaps h.

Corresponding corners of the body portion of the box are formed from a blank in a similar manner. Such a corner is shown in Fig.3, in which the parts corresponding with those of Fig. 1 are designated by the same reference letters, primed.

The construction of the corner of the body portion of the box, as illustrated in Fig. 2, is the same as that illustrated in Fig. 1 except that in Fig. 2 the lug-forming flap h is secured to the outside of the panels, while the additional flap is secured to theinside thereof, this being the reverse of the arrangement previously described. Thus, again, this construction provides a box body, the outsideof which is smooth and free from projections other than the lugs formed by the folded flaps 71..

Figs. 4 and 5 illustrate the cooperation of the parts when the two portions of the box are assembled. Fig. 4 shows the box as it would appear when empty or only partially filled, the cover portion in this case fitting completely over and enclosing the body portion, since the two portions are illustrated as of the same height. In this position of the parts, it will be particularly noted that the lugs formed by the folded flaps h and h are vertically spaced or separated a substantial distance as indicated at n. This provides for considerable lost motion between the cover and body portions. The cover can be raised a substantial distance before the lugs engage or interlock.

The purpose of this arrangement is to adapt the box for the packaging of compressible material such, for example, as paper mill products consisting of large envelopes, folded bags, crepe paper or tissue paper. The box can be filled with material of this kind to a point well above the upper edge thereof. Then, when the cover is applied and forced down, the material is compressed and, when the locking lugs eventually snap over each other and engage, the material is held or maintained ,in compressed condition. This enables boxes to be packed very tightly with products such-as. thoseamentioned, so that the products are ,held securely imposition and prevented from shifting about.

It'will be observed that the locking lugs are formed from relatively narrow. flaps which are adjacent the free edges of the respective box portions, and are spaced from the top and bottom of the cover and body portions, respectively, a distance greater than their own width, preferably a distance equal to the width of the flaps f and ,f'. The amount of vlost motion between the lugs von the two portions is determined by the amount of this spacing, particularlyfin thecover portion. By making these panels wide, the compressible .material maybe piled or packed, in the box body to any height desired above theupper edge thereof.

While I have shown and described the locking lugs as formed from .end'flaps folded back upon themselves so as to provide a double thickness, I .may,,in-some cases, especially if thick corrugated board or heavy fibre board is employed, not fold the flapback .upon itself,..but simply secure it to the adjacent panel, thus providing a lug of only single-thickness.

In either case, however, the important thing is that the lug forming flap and'the additional corner reinforcing .flapare secured to the adjacent panel, on opposite sides thereof, the arrangement of the flaps in this respect for the body portion of the box being the reverse of that for the cover portion. Thus, a strong corner is provided while at the same time the cooperating surface of the two portions of the box adjacent the lugs are kept .smooth and, unobstructed.

What I claim is:

1. A rectangular container comprising body and cover portions each formed from a folded iank of sheet material and each having .side and end panels, the side and end panels of the cover portion being constructed to fit over and surround those of the body portion, two corresponding panels of each portion having at their free edges relatively narrow integral end flaps, each of said flaps being folded to extend from the panel with which it is integral parallel with the adjacent panel to form a lug, the panels with which said flaps are integral also having at their ends additional integral flaps spaced from the free edges of said panels by said relatively narrow flaps, and means for securing both sets of flaps flat against said adjacent panel, the flaps forming the lugs on the body portion being folded on and secured to the outside of the panels and the additional flaps being secured to the inside ofthe. panels, while the flaps forming the lugs on the cover portion are folded on and secured to the inside of the panels and the additional flaps secured to the outside of the panels, whereby a corner joint, having cooperating surfaces smooth except for said lugs, is produced, and when said body and cover portions are assembled and forced together, said lugs snap past each other and interlock to hold said portions together.

2. A rectangular container comprising body and cover, portions each formed from a folded blankof sheet material and each having side and end panelathe side and and panels. of the cover portion being constructed to .fit over and surround those. of the body portion, two corresponding panels of, each portion having at their free edges relatively narrow .integral end flaps, each of saidv flaps being folded to extend from the panel withwhich it is integral parallel with the adjacent vpanel to for a lug, the panels with which said flaps are integral also having at their ends additionalintegral flaps spaced from the free edges of saidpanels by said relatively narrow fiaps,..and means, forsecuring both. sets of flaps fiat against said adjacent panel, the flaps forming the lugs on the body, portion .being folded on.and secured to. the outside of the panels and the additional flaps being secured to the inside of the panels, while the flaps forming the lugs. on the cover portion are folded on and secured to the inside of the panels and the additionalfiaps. secured to the outsideof the panels, whereby a corner joint, having cooperating surfacessmooth except for said lugs, is produced,.said,lugs,being. spaced from the top of the cover portion and the bottom of the body portion.. respectively, a. distance substantially equal tothe width. of said additional flaps, and when said body and cover portions are assembled and forced together, said lugs snap past each other and interlock to hold said portions together.

THOMAS OCHAR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,981,836 .Greve Nov. 20, 1934 1,985,779 Himes Dec. '25, 1934 2,239,233 -Hyndm'an Apr. 22, 1941 2,370,927 Anderson Mar. 6, 1945 2,499,647 James Mar 'l, 1950 FOREIGN EATENTS v Number Country Date 62,290 Austria Nov. 25; 1913 

